C5- Input and Output, The User Connection
How Users See Input and Output
Users submit data (input) to the computer to
get processed information (output)
Output
can be instant reaction to input
Also can be separated by time, distance, or both
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Instant Reaction
Items scanned at supermarket
Produce item name and price at
counter
Forklift obeys operator’s commands
Characters displayed as “typed” text
and stored in pad
Factory workers punch a time
clock as they go from task to task
Produce weekly paychecks and
management reports
Data on checks input into bank
computer
Sales rep enters an order on a pad
Forklift operator speaks to
computer
Input and Output Separated
Charge-card transactions
provide input
Computer processes entries
once a month to prepare
statements
Processed monthly to produce
customer bills
Water samples collected and
input into computer
Used to produce reports that
show patterns of water quality
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User Input: Getting Data using keyboard
Similar to typewriter keyboard
May
be part of a personal computer
May be part of a terminal connected to a computer
in another location
Can be unique to an industry
Keys
on McDonald’s keyboards represent Big Mac
or large fries
Ergonomic keyboards
Pointing devices
Source data automation
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Anatomy of a Keyboard
Designed to reduce or minimize repetitive
strain injury of wrists
Provide more natural, comfortable
position of wrists, arms, and hands
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User Input: Getting Data using Pointing Devices
Used to position a pointer on the screen
Communicate commands to operating system
by clicking a button
Common devices
Mouse
Devices
used for games
Devices used in laptops
Others
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Mouse
The most common pointing
device
Movement on flat surface
causes movement of pointer
on screen
Several types
Mechanical - small ball on
underside rolls as mouse is
moved
Optical - uses a light beam to
monitor mouse movement
Cordless - uses either
infrared or radio waves,
rather than a cord, to
connect to computer
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Trackball and Joystick
Trackball
Variation on mechanical
mouse
User rolls the ball directly
Often built into laptop
computers
Joystick
Short lever with handgrip
Distance and speed of
movement controls
pointer’s position
Pressing trigger causes
actions to take place
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Touchpad and Pointing Stick
Touchpad
Rectangular pressuresensitive pad
Sliding finger across
pad moves pointer
Tapping with finger
recognized as click
Pointing stick
Small pressuresensitive post mounted
in center of keyboard
Pushing post in any
direction moves pointer
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Other Pointing Devices
Graphics tablet
Touch screen
User moves stylus or puck
across board
Used to create or trace precise
drawings
Allow user to touch items on
screen
Position of finger on screen
determines item to be input into
system
Used at kiosks in public places
such as malls
Pen-based computing
Use pen-like stylus to input data
Often used in PDAs or pocket
PCs
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User Input: Getting Data using Source Data
Automation
Use of special equipment to collect data at the
source
Primary areas
Magnetic-ink
character recognition (MICR)
Optical recognition devices
Other sources
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MICR
Uses a machine to
read characters
made of magnetized
particles
Banking industry is
predominant user
Characters preprinted
on lower left-hand
side of check
Amount added by
MICR inscriber when
check is cashed
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Optical Recognition
Uses a light beam to scan data and convert to
electrical signals
Common uses
Scanners are the most common form
Other optical recognition methods
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Common Uses
Scanners at supermarkets
Document imaging - converts
paper documents to
electronic versions
Documents stored on disk
Can be edited or processed by
software
Scanners
Flatbed scanner
Sheetfed scanner
Motorized rollers feed sheet
across scanner head
Handheld scanner
Typically scans one page at a
time
Can be used to scan large bound
documents
Smallest and least accurate
Optical character recognition
(OCR) software required to
convert picture into characters
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Other Optical Recognition Methods
Optical Mark Recognition
Optical character
recognition
Machine senses marks on
piece of paper
Wand reader reads
characters in special
typeface
Bar Codes
A series of vertical marks
Represents a unique code
Universal Product Code
(UPC) used as standard in
supermarkets
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Voice Input
User speaks to computer
Most are speaker-dependent
Speech recognition devices
convert spoken words into
binary digits
Digital Camera
System “learns” user’s voice
Types of systems
User takes photo that is stored
on a chip
Photo can be downloaded to
computer
Discrete word systems - user
must pause between words
Continuous word systems user can speak normally
Use photo-editing software to
enhance
Store permanently on CDs or
DVDs
Photos composed of many
pixels of color
Photos stored on removable
memory card
Other Input Sources
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Video Input
Digital video consists of
series of still frames
Displayed rapidly enough to
give illusion of motion
Web cam used to transmit
video over the Internet
Can capture video from
analog sources with video
capture card
Other Input Sources
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Computer Screen Technology
Computer screens
Printers
Voice output
Music output
Microform
Screen is part of computer’s
monitor
Screen output known as soft
copy
Intangible and temporary
Common forms
Cathode ray tube (CRT)
Flat-panel screens
Smart displays
Output: Information for the User
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CRT Screens
Display text and graphics
Most are in color
Some monochrome monitors
are used in applications that
have no need for color or
graphics
Graphics card converts
signals from the control unit
into the image the user sees
Factors affecting
performance
Factors Affecting Performance
Scan rate
Resolution (clarity) of screen
Measured in pixels- more pixels, the
higher the resolution
Graphics standards exist
Dot pitch
Image refresh rate
The amount of space between dots
The smaller the dot pitch, the
sharper the image
Video memory
A high-speed form of RAM installed
on graphics card
Output: Information for the User
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Graphic Standards
Agree on resolutions, colors, other issues
related to displaying graphics
Super
Video Graphics Adapter (SVGA) is most
common standard
Provides
display
800 (horizontal) x 600 (vertical) pixels on the
Other
varieties of SVGA exist
Support 16 million colors
The
number of colors that can be displayed depends on
amount of video memory
Display screens
Flat-Panel Screens
LCD Technologies
Smart displays
Based
on flat-panel technology
Each contains its own processor
Wireless transmitter-receiver allows user to control
desktop from anywhere in the house
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Produce information on
paper output~ hard copy
Orientation~ Portrait,
Landscape
Two ways of printing
Impact printer
Nonimpact printer
Printers
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Impact Printers
Impact Printers
Physical contact with paper
Line printer
Used for lengthy reports
Nonimpact Printers
Dot-matrix printer
Has print head consisting of
one or more columns of pins
Pins form characters and
images as pattern of dots
Places an image on a page
without physically touching the
page
Laser printer
Uses light beam to help transfer
images to paper
High-quality, high speed
Ink-jet printer
Sprays dots of ink from jet
nozzles
Requires high-quality paper so
ink does not smear
Less expensive than laser
printers
Impact printer and Nonimpact printer
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Voice Output
Voice synthesizers convert data to vocalized
sounds
Two approaches
Synthesis by analysis - analyzes actual human voice,
records and plays back as needed
Synthesis by rule - uses linguistic rules to create
artificial speech
Used in automated telephone-based customer
service applications
Useful when an inquiry would be followed by a short
reply, such as a balance inquiry
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Music Output
Multimedia clips, games, videos include sight and
sound
Speakers placed on side of monitor
Powered sub-woofers produce low-frequency sounds
Musical Instrument Digital Interface (MIDI)
Rules for connecting musical instruments, synthesizers,
and computers
Allows users to set up home studios that rival
capabilities of professional recording studios
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Computer Output Microform (COM)
Output of photographically
reduced images on microfilm
or microfiche
Microfilm - images stored on
continuous roll of film
Microfiche - images stored in
rows and columns on a card
Needs special reader
Common uses
Libraries store back issues
of periodicals
Businesses store large
volumes of historical records
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Terminals
Combine input and output capabilities
Dumb terminal
Keyboard
for input and monitor for output
No processing capability
Intelligent terminal
Has
limited memory and a processor
Point-of-sale (POS) terminal
Captures
place
retail sales data when transaction takes
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Business Graphics
Video Graphics
A powerful way to impart
information
Colorful graphics, maps, and
charts help managers compare
data, spot trends, and make
quicker decisions
As underlying data changes,
charts and graphs are instantly
updated
Computer Graphics
A series of video images
Displayed rapidly to give the
impression of motion
Used extensively in television
Also used in computer and
arcade video games
Computer-aided design/computer-aided
manufacturing (CAD/CAM)
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Computer-Aided Design/
Computer-Aided Manufacturing
Creates two- and
three-dimensional
designs
Performs
engineering tests
such as stress tests
Serves as bridge
between design and
manufacturing
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Ethics and Data
Once data is in computer, there are many ways
it can be used
Ethical issues to ponder
Is
it ethical to use a computer to alter photographs?
Is it ethical to erase e-mail messages that may be
of interest to a party in a lawsuit?
Is it ethical to use someone else’s data for your
purposes?
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Objectives
Describe the user relationship with computer input and
output
Explain how data is input into a computer system and
differentiate among various input equipment
Describe how a monitor works and the characteristics that
determine quality
List and describe the different methods of computer output
Differentiate among different kinds of printers
Explain the function of a computer terminal and describe the
types of terminals
Describe the ethical considerations involved in handling
computer data
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